User group default policies implemented

User groups policies implemented
User group default policies : 
```group_type is "PUBLIC" ```
```edit_policy is "NON_EDITABLE" ```
```subscription_policy is "OPEN" ```
User group edit settings view has changed , only Following policy setting is available for user to edit and make changes.

Modification in : 
```filldb.py``` --> commands included for updating already created user groups
```edit_group.html``` -->  Given only following policy option for user group edit settings
```home.py``` --> code included when user loggsin for first time its group policies are set   

[NOTE : Please do "**python manage.py filldb**" after latest pull]